a. Field of Invention
This invention relates to tricyclic acetic acid derivatives, to their preparation and use, and to intermediates used for their preparation.
More specifically, this invention relates to tricyclic acid derivatives in which the tricyclic portion therof is characterized by having an indole portion fused to a cyclopentane, cyclohexane or cycloheptane ring. Still more specifically, the compounds of this invention are characterized as derivatives of one of the following tricyclic acetic acid systems: ##STR1## a. 1,2,3,4-tetrahydrocyclopent[b]indole-3-acetic acid, ##STR2## b. 1,2,3,4-tetrahydrocarbazole-1-acetic acid, or ##STR3## c. 5,6,7,8,9,10-hexahydrocyclohept[b]indole-6-acetic acid, in which the carbon bearing the acetic acid residue is further substituted with a lower alkyl, lower alkenyl or lower cycloalkyl.
The tricyclic acetic acid compounds of this invention possess useful pharmacologic properties; for instance, they exhibit antiinflammatory activity at dose levels which do not elicit undesirable side effects. The foregoing combination of attributes renders the compounds of this invention useful for the treatment of inflammatory conditions.
B. Prior Art
Apparently the closest prior art to the present invention is a report by H. Sakakibara and T. Kobayashi, Tetrahedron, 22, 2475 (1966), describing the preparation of 1,2,3,4-tetrahydrocarbazole-1-acetic acid. Pharmacologic properties for the compound are not mentioned. The latter compound is distinguished from the compounds of the present invention by its structural arrangement and its pharmacologic properties. More particularly, it is distinguished readily by the fact that it lacks a fully substituted carbon atom at position 1 of the carbazole-1-acetic acid system and secondly the compound lacks antiinflammatory activity when tested in standard pharmacologic tests, see below, in which the compounds of this invention exhibit substantial antiinflammatory effects.
Other prior art, although structurally further removed, includes a report by G. R. Allen, Jr., J. Heterocycl. Chem., 7, 239 (1970), describing the preparation of 1,2,3,4-tetrahydrocarbazole-2-carboxylic acid and its corresponding 6-methoxy derivative (see also Belgian Pat. No. 771598, issued Feb. 21, 1972).